Support is growing among scientists for a controversial theory that all the Earth's water - including oceans, lakes and icecaps - originated from blackened snowball comets that even now are falling from space by the millions.

Papers presented Tuesday at the American Geophysical Union meeting, along with studies reported from Europe and Canada, are slowly adding scientific weight to a concept that once threatened to undermine the career of University of Iowa physicist Louis A. Frank.The findings, Frank said Tuesday, are beginning to ease the professional pain he first endured after publishing the theory two years ago.

"No one has yet found data to show the comets don't exist," he said. The support helps, but Frank admitted, "My life would certainly have been easier" if his snowballs-from-space theory had never been published.

The Iowa scientist based his theory on data gathered from 1981 to 1986 by the Dynamics Explorer I satellite. In pictures taken to study air glow around the Earth, Frank found unexplained holes that appeared to have been punched through the upper atmosphere.

He puzzled over the problem for months and discarded dozens of possible answers before concluding that the only thing that could make the holes were 100-ton comets made of ice and covered with a black hydrocarbon. And he calculated they were falling to Earth at the rate of 10 million a year.

The comets, which are actually ice balls, would come apart as they neared the Earth and would then flash to vapor in the atmosphere, Frank said. Eventually, the vapor fell as rain and joined the Earth's water cycle.

He calculated that the snowballs, measuring about 30 feet across each, contributed the equivalent of one inch of water all over the Earth's surface every 10,000 years.